1. Field of the Invention
The present invention relates to medical devices and procedures for applying localized heat to a site in the patient's body, particularly for purposes such as sterilization of a female patient by closing of the fallopian tubes.
2. Description of the Prior Art
The prior art includes devices and procedures for applying localized heat to a site in a patient's body for a number of purposes, generally including altering, removing or destroying tissue in the patient's body.
U.S. Pat. Nos. 4,773,413 and 4,662,368 both to Hussein et al. disclose a localized heat applying medical device powered by laser energy transmitted through an elongated conduit. The heat applying device includes a bulbous heat generating element, having an aperture in the forward end of the device permitting a portion of the laser energy to be transmitted out the aperture and directly applied to the patient's body tissue. The devices disclosed in Hussein et al. are particularly designed for use in treating cardiovascular disease by removing arteriosclerotic deposits from blood vessels. Commercial embodiments of the Hussein et al. device are marketed by LaserControl Medical Systems Division of Trimedyne, Inc., of Santa Ana, Calif. One such commercially available device is marketed as the SpectraProbe.TM.-80, which is designed such that approximately eighty percent of the laser energy transmitted thereto is emitted through the optical aperture of the end of the device. The SpectraProbe.TM.-80 has a tip diameter of about 2.5 millimeters.
German Patent No. 2,826,383, published Dec. 20, 1979, of Eichler, et al., discloses a laser probe placed directly against or inserted into the patient's tissue for treating the same.
It is also known to use laser powered devices in hysteroscopic procedures. For example, a surgical procedure referred to as an "endometrial ablation" has been recently developed as an alternative to hysterectomy for treatment of excessive uterine bleeding. In this procedure, an Nd:YAG laser is used to destroy the entire endometrium lining the uterus. An optical fiber is inserted in the uterus by means of a hysteroscope to conduct the laser energy to the endometrium. With the aid of a parallel optical viewing fiber of the hysteroscope, the end of the laser transmitting fiber is slowly moved across the surface of the endometrium so that the laser energy penetrates and destroys the endometrium so that the laser energy penetrates and destroys the endometrium which is on the order of three millimeters thick. Typical prior art procedures have utilized a bare optical fiber for transmitting the laser energy. Two techniques have been developed. By one technique, the end of the bare optic fiber is actually touched to the endometrium in a "dragging" procedure. By a second technique, generally referred to as "blanching", the bare tip of the optic fiber is held several millimeters away from the endometrium. These techniques are generally described in Daniell et al., "Photodynamic Ablation of the Endometrium with the ND:YAG Laser Hysteroscopically as a Treatment of Menorrhagia", Colposcopy and Gynecologic Laser Surgery, Volume 2, No. 1, 1986; Mackety, "Alternative to Hysterectomy: Endometrial Ablation by Laser Photovaporization", Today's OR Nurse, Volume 8, No. 4; and Goldrath et al., "Laser Photovaporization of Endometrium for the Treatment of Menorrhagia", Am. J. Obstet. Gynecol., Volume 140, No. 1, page 14, May 1, 1981.
The Goldrath et al. and Daniell et al. articles cited above, both suggest that patients undergoing an endometrial ablation procedure will probably be sterile following the procedure. The work of Goldrath et al. and Daniell et al. was not directed to the end purpose of sterilization, but it was observed as a side effect of the treatment. For reasons further described herein, it is believed that the cause of the sterility observed by Goldrath et al. and Daniell et al. was the destruction of the patient's endometrium.
A recent improvement upon the endometrial ablation procedure, wherein a heat generating tip is attached to the end of the laser transmitting conduit, with the tip being designed to laterally emit a portion of the laser energy is disclosed in Everett et al. pending Application No. PCT/US89/02492 filed Jun. 7, 1989, which has been published in INTERNATIONAL PUBLICATION NO. WO 89/11834 on Dec. 14, 1989. That application is a continuation-in-part of U.S. patent application Ser. No. 07/205,218 filed Jun. 10, 1988.
In all of the endometrial ablation procedures set forth in the references discussed above, the treatment is directed to the endometrium, that is the lining of the uterine cavity, for the purpose of destroying that lining to prevent excessive bleeding. The procedures are not directed to the purpose of closing the fallopian tubes to induce sterilization. Furthermore, the endometrial ablation procedures do not involve any substantial fixed contact of the tip of the laser fiber, or of a heating device on the end of the laser fiber, with the tissue, but rather involve a continuous movement of the tip while dragging it across, or moving it while held a slight distance away from, the tissue.